US9158951B2 - Laser scanning modules embodying silicone scan element with torsional hinges - Google Patents

Abstract

A laser scanning module employs a scan mirror and magnet rotor subassembly supported by a stationary stator structure. The scan mirror and magnet rotor subassembly includes: a silicone frame having a pair of silicone torsional hinges (i.e. posts) aligned along a scan axis and a supported by a pair of support elements associated with the stator structure, to support the scan mirror and magnet rotor subassembly. When the scan mirror and magnet rotor subassembly is rotated about its scan axis, by forces generated by an electromagnetic coil structure acting on the permanent magnet mounted on silicone frame, the silicone torsional hinges are elastically distorted and generate linear restoring forces which return the rotor subassembly back to its home position about the scan axis.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. patent application Ser. No. 13/367,047 for Laser Scanning Modules Embodying Silicone Scan Element with Torsional Hinges filed Feb. 6, 2012 (and published Aug. 8, 2013 as U.S. Patent Application Publication No. 2013/0200158), now U.S. Pat. No. 8,915,439. Each of the foregoing patent application, patent publication, and patent is hereby incorporated by reference in its entirety.

FIELD OF DISCLOSURE

The present disclosure relates to improvements in laser scanning modules, and more particularly to improvements in laser scanning assemblies employed therein.

BACKGROUND

The use of laser scanning bar code symbol reading engines is well known in the art. Applications include: hand-held products; reverse-vending machines; and the like.

Currently, various types of laser scanning mechanisms have been developed for scanning laser beams across bar code symbols. Such laser scanning mechanisms include shaft-based laser scanning mechanisms; hinge-based laser scanning mechanisms; torsional-based laser scanning mechanisms; and flipper-based laser scanning mechanisms.

Conventional shaft-based scanning mechanisms suffer from a number of shortcomings and drawbacks. In particular, prior art shaft-based scanning assemblies suffer from friction-related uncertainty and reliability problems. When using a magnet to generate the return force, the resonant laser scanning system becomes unstable when subjected to excessive external forces.

Conventional silicone hinge-based laser scanning assemblies suffer from scan motion imprecision, due to the fact that such prior art scanning assemblies do not have a fixed scanning axis. Consequently, mirror scan mirror motion does not undergo perfect rotation, and thus, scan beam motion does not follow near ideal linear scanning motion. Also, when subjected to high G forces, additional motion limiters are required to prevent excessive motion. However, these extra motion limiters add complexity to the final laser scanning assembly.

Also, in conventional silicone hinge-based laser scanning assemblies, the moving part (i.e. rotor structure) which holds the scan mirror and permanent magnet is typically a subassembly of flexible and rigid parts, made from materials such as silicone and thermoplastic, or silicone and copper.

Conventional flipper-based laser scanning mechanisms, used generate scan lines in a laser based barcode scanner, also suffer from a number of shortcomings and drawbacks. In particular, stability of such laser scanning mechanisms directly affects the performance of the laser scanner.

Thus, there is great need in the art for new and improved laser scanning assemblies, which avoid the shortcomings and drawbacks of the prior art scanning methods and apparatus.

SUMMARY

A primary object of the present disclosure is to provide a new and improved laser scanning element and module, which overcomes the shortcomings and drawbacks of the prior art laser scanning methods and apparatus.

Another object is to provide a laser scanning assembly employing a silicone frame having two narrow neck areas (e.g. having circular or rectangular cross-sectional dimensions), and functioning as torsion posts, to form a virtual axis about which a scan mirror and permanent magnet on a rotor subassembly are rotated, to create scanning motion similar to that supported by conventional shaft-based laser scanning mechanism, but without the shortcomings and drawbacks associated therewith.

Another object is to provide such a laser scanning assembly, wherein the silicone frame ensures symmetric resonant oscillation.

Another object is to provide such a laser scanning assembly, wherein the torsion posts in the silicone frame function as springs which generate returning forces to the scan mirror and magnet rotor subassembly, when the rotor subassembly is rotated about the virtual scan axis by forces generated by an electromagnetic coil structure and acting on the permanent magnet supported on the rotor subassembly.

Another object is to provide such a laser scanning assembly, wherein the silicone frame and a stationary stator structure incorporated built-in (i.e. integrated) motion limiters that provide precise scan angle limiting, and high G-force motion limiting in all directions, and eliminate the need for external means for achieving motion limiting when subjected to external shock forces.

Another object is to provide such a laser scanning assembly, wherein the silicone rotor frame supports both the scan mirror and magnet on the same side of the virtual rotational axis of the scan mirror and magnet rotor subassembly, significantly simplifying the assembly process during manufacture.

Another object is to provide such a laser scanning assembly, wherein its silicone rotor frame can support a scan mirror implemented as a glass mirror or silicon wafer, to provide better scan mirror surface quality and thus enable longer scanning range operation without compromising system performance.

Another object is to provide a laser scanning engine having an improved torsional-based laser scanning assembly, which can be used to replace shaft-based laser scanning engines to provide more reliable laser scanning operation, with less power consumption, and without friction-uncertainty related jamming, or high power consumption related problems.

Another object is to provide an improved torsional-based laser scanning module having that can be easily integrated into all laser scanning products.

Another object is to provide an improved torsional-based laser scanning module employing a single-piece silicone rotor frame that minimizes the space requirements during module integration.

Another object is to provide an improved torsion-based laser scanning assembly that employs a stationary stator structure, secured to the scanning engine chassis/housing, while supporting (i.e. holding) its scan mirror and magnet rotor subassembly at a minimal distance from the electromagnetic coil structure, to allow lower levels of electrical current to drive the electromagnet coil structure and rotate the scan mirror and magnet rotor subassembly about its virtual axis of rotation, in an energy-efficient manner.

Another object of the present disclosure is to provide an improved torsion-based laser scanning module with a torsion-based laser scanning assembly having a scan mirror and magnet rotor subassembly utilizing a molded silicone rotor frame supporting a scan mirror and permanent magnet, and having torsional-hinges (i.e. torsional posts) aligned along a virtual axis of rotation, and molded over a thermoplastic stator frame that is mounted to the scanning engine housing or chassis.

Another object is to provide such a torsion-based laser scanning assembly, wherein its over-molded, silicone torsion posts function as springs that generate returning forces to the scan mirror and magnet rotor subassembly, when the rotor subassembly is rotated about its virtual axis of rotation, by forces generated by an electromagnetic coil structure and acting on the permanent magnet supported on the rotor subassembly, thereby maintaining a stable laser scanning line during in scanning operation.

Another object is to provide a laser scanning engine employing a torsion-based laser scanning assembly, with an over-molded silicone rotor frame that supports the scan mirror on one side of the virtual axis of rotation, and the permanent magnet on the other side thereof.

Another object is to provide such a torsion-based laser scanning module, wherein its over-molded silicone rotor frame will experience minimal performance degradation over time, by being less susceptible to outside contaminants and environmental conditions, and support more stable scanning operation, and simplify assembly and manufacture.

Another object is to provide a laser scanning engine employing a torsion-based laser scanning assembly, with an over-molded silicone rotor frame that minimizes part-to-part variation, thus providing a more consistent laser scanning line during operation.

Another object of the present invention is to provide a laser scanning module that can be used to replace conventional shaft-based laser scanning engines, with a silicone torsional-based engine that consumers less electrical power, and eliminates friction uncertainty related jams, and high-power consumption problems, and which can be implemented using a glass mirror or silicon wafer mirror to provide better scan mirror surface quality required to achieve long range scanning operation.

Another object of the present invention is to provide a new and improved laser scanning assembly and laser scanning module that allows easy integration into all laser scanning products, while minimizing the space requirements for such integration.

These and other objects will become apparent hereinafter and in the Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the objects, the following detailed description of the illustrative embodiments should be read in conjunction with the accompanying drawings in which:

FIG. 1 is a hand-supportable laser scanning bar code symbol reading system, incorporating any one of the laser scanning modules of the illustrative embodiments of the present disclosure;

FIG. 2 is a schematic block diagram showing the system components employed in the laser scanning bar code symbol reading system ofFIG. 1A, including the laser scanning engine of either the first illustrative embodiment shown inFIGS. 4A through 20C, or the second illustrative embodiment shown inFIGS. 21 through 26C;

FIG. 3 sets forth a flow chart describing the major steps performed during the operation of the laser scanning bar code symbol reading system ofFIG. 1;

FIG. 4A is a first perspective view of a first illustrative embodiment of the laser scanning module according to present disclosure, employing a silicone-based torsional hinge scanning element having integrated motion limiters;

FIG. 4B is a second perspective view of the laser scanning module of the first illustrative embodiment;

FIG. 4C is a plan view of the laser scanning module of the first illustrative embodiment;

FIG. 5A is a perspective view of the laser scanning module of the first illustrative embodiment shown inFIG. 4A, with its top printed circuit (PC) board removed;

FIG. 5B is a side view of the laser scanning module of the first illustrative embodiment shown inFIG. 4A, with its top printed circuit (PC) board removed;

FIG. 5C is a plan view of the laser scanning module of the first illustrative embodiment shown inFIG. 4A, with its top printed circuit (PC) board removed;

FIG. 6A is a first partially exploded view of the laser scanning module of the first illustrative embodiment shown inFIGS. 5A through 5C showing the laser scanning mechanism dismounted from the engine housing, and exploded into its electromagnetic coil structure and torsional-hinge based laser scanning assembly;

FIG. 6B is a second partially exploded view of the laser scanning module ofFIGS. 5A through 5C, showing its laser scanning mechanism exploded into its electromagnetic coil structure and laser scanning assembly;

FIG. 7A is a first top perspective view of the module housing employed inFIGS. 6A and 6B, with all components removed therefrom as shown;

FIG. 7B is a second bottom perspective view of the module housing employed inFIGS. 6A and 6B, with all components removed therefrom as shown;

FIG. 8A is a first rear perspective view of the electromagnetic coil structure employed in the laser scanning module ofFIGS. 6A and 6B;

FIG. 8B is a second front perspective view of the electromagnetic coil structure employed in the laser scanning module ofFIGS. 6A and 6B;

FIG. 9A is a front perspective view of the laser scanning assembly of the first illustrative embodiment, shown fully assembled, but removed from its support recess within the module housing shown inFIGS. 6A and 6B;

FIG. 9B is a rear perspective view of the laser scanning assembly of the first illustrative embodiment, shown fully assembled, but removed from its support recess in the module housing shown inFIGS. 6A and 6B;

FIG. 9C is an elevated side view of the laser scanning assembly of the first illustrative embodiment, shown fully assembled, but removed from its support recess within the module housing shown inFIGS. 6A and 6B;

FIG. 9D is an elevated front view of the laser scanning assembly of the first illustrative embodiment, shown fully assembled, but removed from its support within the module housing shown inFIGS. 6A and 6B;

FIG. 9E is a plan view of the laser scanning assembly of the first illustrative embodiment, shown fully assembled, but removed from its support within the module housing shown inFIGS. 6A and 6B;

FIG. 10 is an exploded view of the laser scanning assembly shown inFIGS. 9A through 9E, comprising (i) a thermoplastic frame holder having a front side, a rear side, a support member for support within a cylindrical recess in the module housing, and a pair of support elements provided on the front side, (ii) a silicone frame structure having a pair of torsional hinges (i.e. torsional posts) for torsional mounting the silicone frame between the support elements provided on the front side of the frame holder, and integrated stop posts formed along the top and bottom edges of the silicone frame, (iii) a scan mirror and mirror adhesive for mounting the scan mirror to the front side of the silicone frame, and (iv) a thin permanent magnet and magnet adhesive for mounting the permanent magnet to rear side of the silicone frame;

FIG. 11A is a first perspective view of the laser scanning assembly inFIGS. 9A through 9E, but with the scan mirror and magnet removed, while showing the frame holder and the silicone frame assembled together;

FIG. 1 lB is a cross-sectional view through the central portion of the laser scanning subassembly inFIG. 11A, with its permanent magnet mounted on the rear side of the silicone frame using adhesive;

FIG. 12 is a perspective view of the permanent magnet employed in the laser scanning assembly shown inFIGS. 9A through 9E;

FIG. 13A is a front perspective view of the silicone frame comprising (i) a silicone (injection-molded) frame portion have a recessed region for receiving the scan mirror and adhesive layer, (ii) a pair of torsional support hinges (i.e. torsional support posts) projecting from the top and bottom edges of the frame portion and arranged along the scanning axis (i.e. scan axis) of the laser scanning assembly, (iii) a magnet mounting recess formed within the central region of the rear side of the frame portion for mounting the permanent magnet therein, and (iv) a two pairs of stops formed at the top and bottom ends of the frame portion for limiting scanning element displacement when subjected to external shock forces;

FIG. 13B is a rear perspective view of the silicone frame of the present disclosure, shown comprising (i) the silicone (injection-molded) frame portion have a recessed region for receiving the scan mirror and adhesive, (ii) the pair of torsional support hinges (i.e. torsional support posts) arranged along the scanning axis of the laser scanning assembly, (iii) the magnet mounting recess formed within the central region of the frame portion for mounting the permanent magnet therein, and (iv) the two pairs of stops formed at the top and bottom ends of the frame portion for limiting scanning element displacement when subjected to external shock forces;

FIG. 13C is a cross-sectional view of the silicone frame inFIGS. 13A and 14B, taken along its vertical extent, through the scanning axis of the silicone frame;

FIG. 13D is a top end view of the silicone frame inFIGS. 13A and 13B, showing its first set of motion limiting stops projecting therefrom;

FIG. 13E is a cross-sectional view of the silicone frame inFIGS. 13A and 13B, taken along its horizontal extent, traverse to the scanning axis of the silicone frame;

FIG. 14A is a front perspective of the frame holder employed in the laser scanning assembly shown inFIGS. 9A through 9C, showing its front side, its cylindrical support member for supporting the frame holder within a cylindrical recess formed in the module housing, and its pair of support elements provided on the front side for torsionally-mounted silicone (injection-molded) frame, by its torsional hinges, shown inFIGS. 13A and 13B;

FIG. 14B is a plan view of the frame holder shown inFIG. 14A, typically made from a thermoplastic;

FIG. 14C is an elevated side view front view of the frame holder shown inFIGS. 14A and 14B;

FIG. 15 is a plan view of the silicone illustrating its normal range of scan angle motion about the scan axis in the clockwise the counter-clockwise directions, while the elastically-distorted torsional hinges generate linear restoring/return forces on the scan mirror and magnet rotor subassembly, to return the same to the home position shown inFIG. 9E, during scanning operations;

FIG. 16A is a perspective view of the silicone frame shown inFIGS. 13A through 13E, illustrating the scan angle motion of the scan mirror and magnet rotor subassembly about the scan axis being limited (i.e. stopped) in the counter-clockwise direction, by a two pairs of motion limiters (i.e. silicone stops) projecting from the top and bottom edges of the silicone frame, and striking stop elements extending transversely from the support projections supporting the silicone frame, as the permanent magnet supported on the rear side of the silicone frame is driven by electromagnetic forces produced by the electromagnetic coil structure in the laser scanning module;

FIG. 16B is a plan view of the laser scanning module shown configured inFIG. 15A;

FIG. 17 is a perspective view of the silicone frame shown inFIG. 16, illustrating the torsional twist that the torsional hinges undergone during 12.5 degrees of rotation from the home position, in either the clockwise or counter-clockwise direction, thereby generating an elastic returning force to the silicone frame, the magnitude of which is linearly proportional to the magnitude of the angle of rotation of the silicone frame about its scan axis of rotation;

FIG. 18A is a perspective view of the laser scanning assembly ofFIGS. 9A through 9E, illustrating that the pair of silicone stops on the upper edge of the silicone frame striking corresponding transversely extending stop projections on the thermoplastic frame holder, limiting motion of the scan mirror and magnet rotor subassembly along the z axis/direction when the laser scanning assembly is subjected to external shock forces exceeding a predetermined threshold (e.g. 200 G along z axis);

FIG. 18B is a plan view of the laser scanning assembly shown inFIG. 18A;

FIG. 18C is a perspective view of the silicone frame in the laser scanning assembly shown inFIGS. 18A and 18B, illustrating that the deformation of the silicone torsional hinges/posts along the z axis/direction, limited by the pair of silicone stops on the silicone frame striking corresponding transversely extending stop projections on the thermoplastic frame holder, in response to the laser scanning assembly being subjected to external shock forces exceeding a predetermined threshold along the z axis direction;

FIG. 19A is a perspective view of the laser scanning assembly ofFIGS. 9A through 9E, illustrating that the upper edge of the silicone frame striking the upper frame support projection of the thermoplastic frame holder, thus limiting motion of the scan mirror and magnet rotor subassembly along the y axis direction when the laser scanning assembly is subjected to external shock forces (e.g. 200 G) along the axis direction;

FIG. 19B is an elevated front view of the laser scanning assembly ofFIG. 19A;

FIG. 19C is a perspective view of the silicone frame in the laser scanning assembly shown inFIGS. 19A and 19B, illustrating that the deformation of the silicone torsional hinges/posts along the y axis direction, limited by the upper edge of the silicone frame striking the upper frame support projection on the thermoplastic frame holder, in response to the laser scanning assembly being subjected to external shock forces exceeding a predetermined threshold along the y axis direction;

FIG. 20A is a perspective view of the laser scanning assembly ofFIGS. 9A through 9E, illustrating the silicone left-side stops on the top and bottom edges of the silicone frame striking corresponding stop surfaces of the support from projections on the thermoplastic frame holder, thus limiting motion of the scan mirror and magnet rotor subassembly along the x axis direction when the laser scanning assembly is subjected to external shock forces above a predetermined threshold (e.g. 200 G) along x axis direction;

FIG. 20B is a plan view of the laser scanning assembly ofFIG. 20A, illustrating that the stop on the upper edge of the silicone frame striking corresponding stop surfaces on the frame support projection on the thermoplastic frame holder, and thus limit motion of the scan mirror and magnet rotor subassembly along the x axis direction when the laser scanning assembly is subjected to external shock forces above a predetermined threshold (e.g. 200 G) along x axis direction;

FIG. 20C is a perspective view of the silicone frame in the laser scanning assembly shown inFIGS. 20A and 20B, illustrating that the deformation of the silicone torsional hinges/posts along the x axis direction, limited by the stops on the top and bottom edges of the silicone frame striking corresponding stop surfaces on the top and bottom frame support projections on the thermoplastic frame holder, in response to the laser scanning assembly being subjected to external shock forces exceeding a predetermined threshold (e.g. 200 G) along the x axis direction;

FIG. 21 is a perspective view of the second illustrative embodiment of the laser scanning module according to present disclosure, employing a silicone-based torsional-hinge scanning assembly employing omni-directional integrated motion limiters;

FIG. 22 is an exploded view of the second illustrative embodiment of the laser scanning module shown inFIG. 21, comprising components including a laser scanning assembly with a silicone torsional-hinge scanning element (i.e. scan mirror and magnet rotor) driven by an electromagnetic coil structure, supplied with electrical current by drive circuits on a PC board mounted on the top side of the module housing;

FIG. 23 is a perspective view of the laser scanning module shown inFIGS. 21 and 22, with its housing cover removed for purposes of illustration;

FIG. 24 is a first perspective view of the laser scanning module ofFIG. 23, with its top side PC board removed for purposes of illustration;

FIG. 25A is a first perspective view of the laser scanning assembly of the second illustrative embodiment comprising (i) a frame holder, (ii) a silicone frame having a scan mirror mounting surface, a magnet mounting surface and a pair of torsional silicone hinges (i.e. posts) connected to the frame holder by way of the silicone torsional hinges (i.e. hinge posts) aligned along an axis of rotation (i.e. scanning axis), (iii) scan mirror mounted to the scan mirror mounting surface, (iv) a magnet mounted to the magnet mounting surface, and (v) an omni-directional motion limiting structure mounted over the magnet on the rear side of the silicone frame;

FIG. 25B is an exploded view of the laser scanning assembly of the second illustrative embodiment shown inFIG. 25A, with the scan mirror mounted on a front surface of the silicone frame, and permanent magnet mounted on a rear surface of the silicone frame;

FIG. 25C is a second perspective view of the laser scanning assembly shown inFIG. 25A;

FIG. 25D is an exploded view of the laser scanning assembly shown inFIGS. 25A and 25C;

FIG. 25E is a perspective exploded view of the scan mirror and magnet rotor subassembly employed in the laser scanning assembly shown inFIGS. 25A through 25D;

FIG. 25F is a second perspective exploded view of the scan mirror and magnet rotor subassembly employed in the laser scanning assembly shown inFIGS. 25A through 25D;

FIG. 26A is a perspective view of the silicone torsional-type scan mirror and magnet frame (i.e. rotor) employed in the laser scanning assembly shown inFIGS. 25A and 25C, showing its torsional hinge posts aligned along the scan axis thereof;

FIG. 26B is a plan view of the silicone frame shown inFIG. 26A, showing its silicone hinges aligned along an axis of rotation (i.e. scan axis);

FIG. 26C is a first elevated side view of the silicone frame, shown inFIGS. 26A and 26B, and illustrating the torsional hinges aligned along the scan axis;

FIG. 26D is a cross-sectional view of the silicone frame (i.e. rotor) taken alongline26D-26D inFIG. 26C;

FIG. 27A is a perspective view of the thermoplastic frame holder employed in the laser scanning assembly shown inFIGS. 25A and 25C, removed from the laser scanning assembly;

FIG. 27B is a plan view of the thermoplastic frame holder shown inFIG. 27A;

FIG. 27C is an elevated front view of the thermoplastic frame holder shown inFIGS. 27A and 27B;

FIG. 27D is a cross-sectional view of the thermoplastic frame holder (i.e. stator) taken alongline26D-26D inFIG. 27C;

FIG. 28A is a perspective view of the laser scanning assembly shown inFIGS. 25A and 25C, with its scan mirror and magnet rotor subassembly configured in its home position about the scan axis of the laser scanning assembly (i.e. 35 degrees from the reference line shown);

FIG. 28B is a plan view of the laser scanning assembly shown inFIG. 28A, indicating the home position of the scan mirror and magnet rotor subassembly about the scan axis of the laser scanning assembly (i.e. 35 degrees from the reference line shown);

FIG. 29A is a perspective view of the laser scanning assembly ofFIG. 25A, rotated 20 degrees about the scan axis from the home position, whereupon the integrated rotation limiting occurs;

FIG. 29B is a plan view of the laser scanning assembly shown inFIG. 29A, wherein the scan mirror and magnet rotor subassembly is stopped at 20 degrees rotation about the scan axis, from the home position;

FIG. 29C is a perspective view of the silicone torsionally-distorted frame shown inFIGS. 29A and 29B;

FIG. 29D is a plan view of the silicone torsionally-distorted frame shown inFIG. 29C, wherein silicone hinges have undergone 20 degrees of twist during maximum rotation about the scan axis;

FIG. 29E is a perspective view of the laser scanning assembly ofFIG. 25A, as configured with its scan mirror and magnet rotor subassembly rotated to an extreme clockwise position, and showing the integrated motion limiter striking the thermoplastic frame holder, and limiting the rotation of the scan mirror and magnet rotor subassembly;

FIG. 29F is a perspective view of the laser scanning assembly ofFIG. 25A, as configured with its scan mirror and magnet rotor subassembly rotated to an extreme counter-clockwise position, and showing the integrated motion limiter striking the thermoplastic frame holder, and limiting the rotation of the scan mirror and magnet rotor subassembly;

FIG. 30A is a perspective front view of the laser scanning assembly ofFIG. 25A, subjected to external shock forces exceeding a particular threshold, with displacement of the scan mirror and magnet rotor subassembly limited along the x axis direction, by the integrated motion limiters;

FIG. 30B is a plan view of the laser scanning assembly configured as shown inFIG. 30A;

FIG. 30C is a perspective rear view of the laser scanning assembly ofFIG. 25A, subjected to external shock forces exceeding a particular threshold, and showing the displacement of the scan mirror and magnet rotor subassembly limited along the x axis direction, by the integrated motion limiters contacting the thermoplastic frame holder, as shown;

FIG. 30D is a perspective view of the silicone torsionally-supported frame in the configured laser scanning assembly ofFIGS. 30A through 30C, showing the displacement of the silicone torsional hinges along the x axis direction;

FIG. 30E is an elevated side view of the silicone torsionally-supported frame shown inFIG. 30D;

FIG. 31A is a perspective front view of the laser scanning assembly ofFIG. 25A, subjected to external shock forces exceeding a particular threshold, with displacement of the scan mirror and magnet rotor subassembly limited along the y axis direction, by the integrated motion limiters;

FIG. 31B is an elevated side view of the laser scanning assembly configured as shown inFIG. 31A;

FIG. 31C is a perspective rear view of the laser scanning assembly ofFIG. 25A, subjected to external shock forces exceeding a particular threshold, and showing the displacement of the scan mirror and magnet rotor subassembly limited along the y axis direction, by the integrated motion limiters contacting the thermoplastic frame holder, as shown;

FIG. 31D is a perspective view of the silicone torsionally-supported frame in the configured laser scanning assembly ofFIGS. 31A through 31C, showing the displacement of the silicone torsional hinges along the y axis direction;

FIG. 32A is a perspective front view of the laser scanning assembly ofFIG. 25A, subjected to external shock forces exceeding a particular threshold, with displacement of the scan mirror and magnet rotor subassembly limited along the z axis direction, by the integrated motion limiters;

FIG. 32B is a plan view of the laser scanning assembly configured as shown inFIG. 32A;

FIG. 32C is a perspective rear view of the laser scanning assembly ofFIG. 25A, subjected to external shock forces exceeding a particular threshold, and showing the displacement of the scan mirror and magnet rotor subassembly limited along the z axis direction, by the integrated motion limiters contacting the thermoplastic frame holder, as shown;

FIG. 32D is a perspective view of the silicone torsionally-supported frame in the configured laser scanning assembly ofFIGS. 32A through 32C, showing the displacement of the silicone torsional hinges along the z axis direction; and

FIG. 32E is an elevated side view of the silicone torsionally-supported frame shown inFIG. 32D.

DETAILED DESCRIPTION

Referring to the figures in the accompanying drawings, the various illustrative embodiments of the present invention will be described in greater detail, wherein like elements will be indicated using like reference numerals.

Overview on the Laser Scanning Module

Laser scanning modules (i.e. engines)30 and60 are disclosed for use in diverse kinds of laser scanning bar code symbol reading systems1 including, but not limited to, the hand-supportable laser scanning system1 shown inFIG. 1. However, it is understood that theselaser scanning modules30 and60 can be installed in other types of laser scanning systems, other than hand-supportable systems, such as POS-projection, countertop, and industrial type laser scanning systems.

As shown inFIGS. 1 and 2, the laser scanning bar code symbol reading system1 comprises: a hand-supportable housing2 having a head portion and a handle portion supporting the head portion; alight transmission window3 integrated with the head portion of thehousing2; a manually-actuatedtrigger switch4 for activating a laser scanning module or engine (e.g. asFIGS. 4A through 20C, or as shown inFIGS. 21 through 32E) supporting alaser scanning field5; an IR-basedobject detection subsystem6 for generating an IR beam within the laser scanning field, as shown inFIG. 2, for automatically detecting the presence of an object in the laser scanning field, and generating a trigger event signal when an object is automatically detected in the scanning field.

As shown inFIG. 2, thelaser scanning module30,60 further comprises: alaser drive circuit15 for receiving control signals fromsystem controller16, and in response thereto, generating and delivering laser (diode) drive current signals to alaser source17 having beam shaping optics to produce alaser scanning beam18 that is repeatedly scanned across the laser scanning field; light collection optics (e.g. light collection mirror)19 for collecting light reflected/scattered from scanned object in thescanning field5, and a photo-detector20 for detecting the intensity of collected light and generating an analog scan data signal corresponding to the detected light intensity during scanning operations.

In the illustrative embodiment, thelaser scanning module30,60 further comprises: an analog scan data signal processor/digitizer21 for (i) processing the analog scan data signals, (ii) converting the processed analog scan data signals into digital scan data signals, and then (iii) converting these digital scan data signals into digital words representative of the relative width of the bars and spaces in the scanned code symbol structure; a programmeddecode processor22 for decode processing digitized data signals, and generating symbol character data representative of each bar code symbol scanned by either a visible or invisible laser scanning beam; an input/output (I/O)communication interface module23 for interfacing with a host communication system and transmitting symbol character data thereto via wired or wireless communication links that are supported by the symbol reader and host system; and system (micro)controller16 for generating the necessary control signals for controlling operations within the laser scanning bar code symbol reading system1.Components20,21,22, and23 can be realized on one or more external PC boards, integrated with thelaser scanning module30,60, or on an external PC boards interfaced withmodule30,60 using a flexible ribbon cable, in a manner well known in the art.

Preferably, IR-basedobject detection subsystem6 is mounted in the front of itslight transmission window3 so that the IR light transmitter and IR light receiver components ofsubsystem6 have an unobstructed view of an object within the laser scanning field of the system, as shown inFIG. 1. Also, the IR objectpresence detection module6 can transmit into thescanning field5, IR signals having a continuous low-intensity output level, or having a pulsed higher-intensity output level, which may be used under some conditions to increase the object detection range of the system. In alternative embodiments, the IR light transmitter and IR light receiver components can be realized as visible light (e.g. red light) transmitter and visible light (e.g. red light) receiver components, respectively, well known in the art. Typically the object detecting light beam will be modulated and synchronously detected, as taught in U.S. Pat. No. 5,340,971, incorporated herein by reference.

Depending on the application, theobject detection subsystem6 or the manually-actuatedtrigger switch4 and related circuitry, can be enabled for the purpose of generating a trigger event signal and supporting either a manually-triggered mode of operation, or an automatically-triggered mode of operation, as required by the end-user application at hand.

As shown inFIGS. 2 and 10, thelaser scanning module30,60 generally comprises a number of subcomponents, namely:laser scanning assembly24 including a scan mirror andmagnet rotor subassembly25 torsionally supported by a stationary frame holder (i.e. stator structure)26, wherein the silicone frame structure supports a reflective element (e.g. scan mirror)27 and a permanent magnetic28; anelectromagnetic coil structure29 including one or more wire coils wound on a coil support structure (e.g. bobbin) and driven by scanner coil drive andsense circuit15, generating an electrical drive signal to drive the electromagnetic coil and force thelaser scanning assembly24 in oscillation about its scan axis; alaser beam source17 for producing avisible laser beam18; abeam deflecting mirror31 for deflecting thelaser beam18 from itssource17, as incident beam18A towards the mirror component of thelaser scanning assembly24, which sweeps the deflectedlaser beam18 across thelaser scanning field5 and abar code symbol32 that might be simultaneously present therein during system operation. During scanner operation, theelectromagnetic coil29 generates magnetic forces on opposite poles of thepermanent magnet28, during scanning operation, and causes thescanning assembly24 to oscillate about itsscanning axis32, in a manner which will be described in greater detail hereinafter.

In general, system1 supports both an automatic-triggered mode of operation and a manually-triggered triggered mode of operation. During either mode of operation, a triggering event signal is generated (e.g. byobject detector6 or by manual trigger switch4), and in response thereto, thelaser scanning module30,60 generates and projects a laser scanning beam through thelight transmission window3, and across the laser scanning field external to the hand-supportable housing, for scanning an object in thescanning field5. Thelaser scanning assembly24 repeatedly scans the laser beam18A across acode symbol32 residing on an object in thelaser scanning field5. Thelight collection optics19 collects light reflected/scattered from scanned code symbols on the object in the scanning field, and the photo-detector20 automatically detects the intensity of collected light (i.e. photonic energy) and generates an analog scan data signal corresponding to the light intensity detected during scanning operations. The analog scan data signal processor/digitizer21 processes the analog scan data signals, converts the processed analog scan data signals into digitized data signals, and then the digital data signals are converted into digital words. The programmeddecode processor22 decode processes the digital words, and generates symbol character data representative of each bar code symbol scanned by laser scanning beam. Symbol character data corresponding to the bar codes read by thedecoder22 is then transmitted to the host system via the I/O communication interface23 which may support either a wired and/or wireless communication link, well known in the art. During object detection and laser scanning operations, thesystem controller16 generates the necessary control signals for controlling operations within the laser scanning bar code symbol reading system.

Referring toFIG. 3, a method of reading bar code symbols and controlling operations within the laser scanning bar code reader1 will be described in greater detail.

As indicated inFIG. 3, the process orchestrated by thesystem controller16 begins at the START Block. Then at Block A inFIG. 3, the system controller determines if a trigger event has occurred (i.e. whether or not trigger signal has been manually generated bytrigger4, or automatically produced by IR detection subsystem6). In the event that a trigger event has been detected at Block A, then at Block B thesystem controller16 directs thelaser scanning module24 to scan the detected object with a laser beam generated by theVLD17. If not, the system resides at Block A waiting for a trigger event signal.

At Block C, thedecode processor22 runs a decode algorithm on the captured scan data, and if at Block D, a bar code symbol is decoded, then at Block E, the produced symbol character data is transmitted to the host system, and the system controller returns to Block A. If, however, at Block D a bar code symbol is not decoded, then thesystem controller16 determines at Block F whether or not the maximum scan attempt threshold has been reached, and if not, then thesystem controller16 returns to Block B, and resumes the flow as indicated. However, if at Block F1, thesystem controller16 determines that the maximum scan attempt threshold has been accomplished, then thesystem controller16 proceeds to Block F2 and sends a Failure to Decode notification to the operator and returns to Block A.

Having described the method of operation above, it is appropriate at this juncture to describe the illustrative embodiments of the laser scanning modules that are employed in the code symbol reading system.

Specification of the First Illustrative Embodiment of the Laser Scanning Module According to Present Disclosure, Employing a Silicone Torsional Hinge Scanning Element and an Omni-Directional Motion Limiting Subsystem

As shown inFIGS. 4A through 4C, thelaser scanning module30 according to a first illustrative embodiment comprises: an engine housing orframework35 having multiple sides, namely opposing sides, a front side with alight transmission aperture36, and opposing rear side, a bottom side and opposing top side; alaser scanning assembly24′ having a scan mirror and magnet rotor subassembly36 (i) having silicone scan mirror andmagnet support frame36 withtorsional posts36A and36B, supported from a thermoplastic hinge holder (i.e. stationary stator structure)37 mounted in theengine housing35, and (ii) driven by electromagnetic force field generated by anelectromagnetic coil structure29 mounted in theengine housing35; and at least onePC board40, mounted on at least one side of the module housing, and having one or more electronic circuits formed thereon implementing the functions of the various subsystems described in the system block diagram shown inFIG. 3.

As shown inFIGS. 5A and 5C, theelectromagnetic coil structure29′ is mounted within themodule housing35 on the rear side of thelaser scanning assembly24. Theelectromagnetic coil structure29′ has a plurality of electrically conductive pins connected to its coil windings, which are driven by scanner drive andsense circuits15. The function of theelectromagnetic coil29′ is to exert electromagnetic forces on apermanent magnet28′ retained in the scan mirror andmagnet rotor subassembly25′, and cause the scan mirror andmagnetic rotor subassembly25′ to oscillate about its scan axis39 (from its home position shown inFIG. 9E), and sweep thelaser scanning beam18 across thelaser scanning field5.

In the illustrative embodiment shown inFIGS. 8A and 8C, the electromagneticcoil support structure19 has the shape of a bobbin, formed by a pail of parallel flanges extending from acylindrical portion19. About the cylindrical portion, a primary drive coil41A is wound and terminated in a first pair of electrically-conductive pins42A and42B. Also, a sense coil41B is wound about the electromagneticcoil support structure4 and terminated in a second pair of electrically-conductive pins42. As shown inFIG. 8B, the electricallyconductive pins42 are arranged in a linear array configuration, but may be arranged in a different configuration, in different illustrative embodiments, as may be required or desired.

As shown inFIGS. 9A,9B,13A through13E, a silicone scan mirror andmagnet frame36 comprises: having afirst side36A for mounting ascan mirror27′; asecond side36B for mounting apermanent magnet28′; and a pair of silicone torsional hinges36C and36D aligned along ascan axis39 passing through thesilicone frame36. As shown inFIGS. 9C and 10, thescan mirror27′ is mounted on the first side of thesilicone frame36A by a first layer ofadhesive43. Thepermanent magnet28′ is mounted on said second side of thesilicone frame36B using a second layer ofadhesive44. In the illustrative embodiment, the cross-sectional dimensions of thetorsional posts36E and36F are circular, but can be rectangular or other regular or irregular geometrical shapes, as may be required or desired, for a particular application. Also, in the illustrative embodiment, thefirst side36A and thesecond side36B of thesilicone frame36 reside on the same side of thescan axis39 passing through thesilicone frame36. Also, thesilicone frame36 has a firstcentral opening361 on thefront side36H, and a wider second opening36J on thesecond side36B, for mountingmagnet28′ to mirror27′.

As will be described in greater detail hereinafter, the pair of silicone torsional hinges36A and36D undergo elastically-deformation when the electromagnet coil drives the rotor away from its home position, as shown inFIG. 9E, to its maximum clockwise and counter-clockwise rotations about the scan axis, and therewhile generates elastic returning force to the scan mirror andmagnet rotor subassembly25, having a magnitude which is linearly proportional to the magnitude of the angle of rotation of said scan mirror andmagnet rotor subassembly25 about saidscan axis39.

As shown inFIGS. 13A and 13B, thesilicone frame36 comprises: an upper end oredge36G having a first pair ofstops46A and46B formed on opposite sides of thetorsional post36C; and a lower end oredge36H having a second pair of stops46C and46D formed on opposite sides of thetorsional post36D. As illustrated inFIGS. 16A through 20C, the spacing of thesestops46A,46B,46C, and46D is selected so that these silicone post-like stops effectively limit the angular and translational displacement of the scan mirror andmagnet rotor subassembly25′ when the laser scanning assembly is subjected to external shock forces.

As shown inFIGS. 14A through 14C, thestator structure26′ comprises: aframe holder26A′ having afront side26B′ and arear side26C′; asupport member26D′ for supporting thesilicone frame36 within acylindrical recess35B in themodule housing35 shown inFIG. 5A; and a pair of top andbottom support elements26E′ and26F′ provided on the front side of the frame holder, in a spaced apart and aligned manner. As arranged, the pair of silicone torsional hinges36E and36F are mounted to or throughapertures26G′ and26H′ in thesupport elements26E′ and26F′, respectively, and torsionally support the scan mirror and magnet rotor subassembly between the support elements and allow the scan mirror andmagnet rotor assembly25′ to oscillate freely about thescan axis39 passing through the silicone torsional hinges36E and36F and thesupport elements26E′ and26F′.

As shown inFIGS. 14A through 14C, the upper frame support element (i.e. projection)26′ further comprises a first pair of projections261′ and26J′ that extend transversely from the distal end of the upperframe support element26E′, for engaging with the first pair of uppersilicone stop posts46A and46B, as illustrated inFIGS. 16A through 20C, and stopping clockwise and counter-clockwise rotation, when the laser scanning module is subjected to external shock forces exceeding a predetermined threshold (e.g. 200 G). Also, the lower frame support element (i.e. projection)26F′ further comprises a second pair of projections26K′ and26L′ that extend transversely from the distal end of the lowerframe support element26F′, for engaging with the second pair of upper silicone stop posts46C and46D, as illustrated inFIGS. 16A through 20C, and stopping clockwise and counter-clockwise rotation, when the laser scanning module is subjected to external shock forces exceeding a predetermined threshold (e.g. 200 G).

As shown inFIGS. 13B and 14A, thesilicone frame36 has arear portion36B, whereas thethermoplastic frame holder26 has afront surface26B′. As illustrated inFIG. 18B, when the laser scanning assembly is subject to external shock forces exceeding a particular threshold along the −Z axis direction, then therear portion36D of thesilicon frame36 engages thefront surface26B′ of theframe holder26′, thereby limiting the linear displacement of the scan mirror andmagnet rotor subassembly25′ along the −Z axis direction. As illustrated inFIGS. 18A through 18C, then when the laser scanning assembly is subject to external shock forces exceeding a particular threshold along the +Z axis direction, then thesilicone stop posts46A and46B, and46C and46D strike the corresponding stop projections261′ and26J′, and26K′ and26L′, respectively, thereby limiting the linear displacement of the scan mirror andmagnet rotor subassembly25′ along the +Z axis direction.

Specification of the Omni-Directional Motion Limiting Structures Integrated within the Laser Scanning Assembly of First Illustrative Embodiment

As will be illustrated in greater detail hereinafter, when the laser scanning module is subjected to external shock forces, and thelaser scanning assembly24′ undergoes extreme limits of rotational motion about the virtual axis ofrotation39, the function of the omni-directional motion stop projection is to strike corresponding stops surfaces on thestationary stator structure26′, thereby limiting the angular and translational motion of thescanning subassembly24′, while preventing damage to the laser scanning assembly.

FIG. 15 illustrates the normal range of scan angle motion about thescan axis39 in the clockwise the counter-clockwise directions, while the elastically-distorted torsional hinges (i.e. posts)26E′ and26F′ generate linear restoring/return forces on the scan mirror andmagnet rotor subassembly25′, to return the same to the home position shown inFIG. 9E, during scanning operations.

FIGS.10A1 and10A2 illustrate the rotational motion of the scan mirror andmagnet rotor subassembly25′, about its virtual axis of rotation, in response to magnetic forces generated by theelectromagnetic coil structure25′, and exerted against the permanent magnet embedded there within.

FIG. 16A illustrates the scan angle motion of the scan mirror and magnet rotor subassembly about thescan axis39 being limited (i.e. stopped) in the counter-clockwise direction, by a pair of motion limiters (i.e. silicone stops)46A,46C projecting from the top and bottom edges of thesilicone frame36, and striking stop elements extending transversely from the support projections supporting the silicone frame, as the permanent magnet supported on the rear side of the silicone frame is driven by electromagnetic forces produced by the electromagnetic coil structure in the laser scanning module.

FIG. 17 illustrates the torsional twist that the torsional hinges36C and36D undergone during 12.5 degrees of rotation from the home position, in either the clockwise or counter-clockwise direction, thereby generating an elastic returning force to thesilicone frame36, the magnitude of which is linearly proportional to the magnitude of the angle of rotation of the silicone frame about its scan axis of rotation.

FIGS. 18A and 18B illustrate that the pair of silicone stops46A and46B on the upper edge of thesilicone frame36 striking corresponding transversely extending stop projections26I′,26J′ on thethermoplastic frame holder26′, and limiting the motion of the scan mirror andmagnet rotor subassembly25′ along the z axis direction when the laser scanning assembly is subjected to external shock forces exceeding a predetermined threshold (e.g. 200 G along z axis).FIG. 18C illustrates the deformation that the silicone torsional hinges (i.e. posts)36E and36F has undergone in the z axis/direction, in the laser scanning assembly ofFIGS. 18A and 18B.

FIGS. 19A and 19B illustrate that the upper end (i.e. edge)36G of thesilicone frame36 striking the upperframe support projection26E′ of the thermoplastic frame holder, thus limiting motion of the scan mirror andmagnet rotor subassembly25′ along the y axis direction when the laser scanning assembly is subjected to external shock forces (e.g. 200 G) along the axis direction.FIG. 19C illustrates that the deformation of the silicone torsional hinges/posts36E and36F along the y axis direction, limited by the upper edge of thesilicone frame36 striking the upperframe support projection26E on the thermoplastic frame holder, in response to thelaser scanning assembly24′ being subjected to external shock forces exceeding a predetermined threshold along the y axis direction, as shown inFIGS. 20A and 20B.

FIGS. 20A and 20B illustrates the silicone left-side stops46A and46C on the top and bottom edges of the silicone frame striking corresponding stop surfaces on theframe support projections26E′,26F′ on thethermoplastic frame holder26′, thus limiting motion of the scan mirror andmagnet rotor subassembly25′ along the x axis direction when the laser scanning assembly is subjected to external shock forces above a predetermined threshold (e.g. 200 G) along x axis direction.FIG. 20C illustrates that the deformation of the silicone torsional hinges/posts36C and36D along the x axis direction, limited by thestops46Am46B on the top and bottom edges of thesilicone frame36 striking corresponding stop surfaces on the top and bottomframe support projections26E′,26F′ on the thermoplastic frame holder, as shown inFIGS. 20A and 20B.

All components of the laser scanning assembly, except for themagnet28′,silicone frame36, and electromagnetic coil windings41A,41B can be a molded as thermoplastic parts using suitable thermoplastic material (e.g. polycarbonate, acrylonitrile butadiene styrene, and/or synthetic polymers known generically as polyamides, etc). Thepermanent magnet28′ can be realized using Neodymium Iron Boron Type N50 magnetic material, or similar material. Theelastomeric frame element36, with integratedtorsional posts36C and36D, can be injection molded from a Liquid Silicone Rubber (LSR) material, such as Momentive Performance #2030 Silicone or Shin-Etsu KE2090-30AB Select Hesive with enhanced adhesive properties. The layer of adhesive43,44 can be aDow Corning 734 adhesive, or similar material, and the primer layer could be a GE SS4004P or similar material.

Specification of the Second Illustrative Embodiment of the Laser Scanning Module According to Present Disclosure, Employing a Silicone Torsional Hinge Scanning Element

As shown inFIGS. 21 through 24, thelaser scanning module60 according to a second illustrative embodiment comprises: an engine housing orframework65 having multiple sides, namely opposing sides, a front side with alight transmission aperture66, and opposing rear side, a bottom side and opposing top side;electromagnetic coil structure29″; alaser scanning assembly24″ having a scan mirror andmagnet rotor subassembly25″ with a silicone basedframe68 torsionally-supported from a frame holder (i.e. stationary stator structure)26″ supported in theengine housing65, and driven by an electromagnetic force field generated by anelectromagnetic coil structure29″ mounted in theengine housing65; and at least onePC board68, mounted on at least one side of the module housing, and having one or more electronic circuits formed thereon implementing the functions of the various subsystems described in the system block diagram shown inFIG. 3.

As shown inFIGS. 22 and 24, theelectromagnetic coil structure29″ is mounted within themodule housing65 on the rear side of thelaser scanning assembly24″. Theelectromagnetic coil structure29″ has a plurality of electrically conductive pins69 connected to its coil windings, which are driven by scanner drive andsense circuits15. The function of theelectromagnetic coil29″ is to exert electromagnetic forces on apermanent magnet28″ retained in the scan mirror andmagnet rotor subassembly25″, and cause the scan mirror andmagnetic rotor subassembly70 to oscillate about its virtual axis ofrotation70, and sweep thelaser scanning beam18 across thelaser scanning field5.

In the illustrative embodiment shown inFIGS. 22 and 24, the electromagneticcoil support structure29″ has the shape of a bobbin, formed by a pair of parallel flanges and extending from a cylindrical portion, about which a primary drive coil71A is wound and terminated in a first pair of electrically-conductive pins. Also, asense coil71B is wound about the electromagneticcoil support structure29″, and terminated in a second pair of electrically-conductive pins. As shown inFIG. 24, the electrically conductive pins69 are arranged in a linear array configuration, but may be arranged in a different configuration, in different illustrative embodiments, as may be required or desired.

As shown inFIGS. 25A through 25D, the laser scanning assembly of the secondillustrative embodiment24″ comprising: (i) aframe holder26″; (ii) asilicone frame68 having a scan mirror mounting surface68A, amagnet mounting surface68B and a pair of torsional silicone hinges (i.e. posts)68E and68F connected to theframe holder26″ by way of the silicone torsional hinges (i.e. hinge posts)68C and68D aligned along an axis of rotation (i.e. scanning axis) and either snap-fitted throughapertures26E″ and26F″, or over-molded to the frame holder; (iii)scan mirror27″ mounted to the scan mirror mounting surface68A; (iv) amagnet28″ mounted to themagnet mounting surface68B; and (v) an omni-directionalmotion limiting structure73 mounted over themagnet28″ on the rear side of the silicone frame. Notably, as best shown inFIGS. 25C and 25F, the omni-directionalmotion limiting structure73 is realized as a thin cross-shaped structure, withwide projections73A,73B,73C and73D extending in each of its four orthogonal directions, namely +X, −X, +Y, −Y, respectively.

FIGS. 26A through 26D illustrate the silicone torsional-type scan mirror and magnet frame (i.e. rotor)25″ employed in thelaser scanning assembly24″, shown inFIGS. 25A and 25C. As shown, the torsional hinge posts68C and68D are aligned along thescan axis70 thereof. The distal portions of each siliconetorsional hinge68C and68D are enlarged greater than the diameter of theintermediate portion68E and68F of the hinge posts68C and68D. As shown inFIG. 26B, the mirror support/mounting surface (i.e. recess)68A is on the opposite side of magnet support/mountingsurface68B, with thetorsional posts68C and68D disposed there between. This results in a symmetrical arrangement of the scan mirror and permanent magnet about thescan axis70.

FIGS. 27A through 27D illustrate thethermoplastic frame holder26″ employed in thelaser scanning assembly24″ shown inFIGS. 25A and 25C, removed from the laser scanning assembly. As shown inFIG. 27A, theframe holder26″ has a frame-like geometry, with acentral opening26C″ with top and bottom edge surfaces26E″ and26F″, and a pair ofapertures26F″ and26G″ formed in the top and bottom portions of theframe holder26″. The distal portions of the hinge posts68C and68D are mounted throughapertures26D″ and26E″, in a tight-fit, or other manner. As shown inFIGS. 27A,27B and27C, acylindrical support post26D″ extends from the frame holder on its right side for mounting in a cylindrical recess65B formed in thelaser module housing65, as shown inFIG. 22. This support post maintains the frame holder stationary at a close distance from theelectromagnetic coil structure29″ so that the coil can exert magnetic forces on the permanent magnet, using preferably the small level of coil drive current, for a given level of voltage across the coil. As shown inFIGS. 27A and 27B, the rear side of theframe holder26″ has integratedmotion stop projections26 disposed on the top and bottom portions thereof.

FIGS. 28A through 28B illustrates the laser scanning assembly shown inFIGS. 25A and 25C, with its scan mirror and magnet rotor subassembly configured in its home position about the scan axis of the laser scanning assembly (i.e. 35 degrees from the reference line shown). The restoring/returning forces generated by distortedtorsional posts68C and68D drive the scan mirror andmagnet rotor subassembly25″ to this home position75 during each and every scanning cycle.

FIGS. 29A and 29B illustrate the laser scanning assembly ofFIG. 25A, rotated 20 degrees about thescan axis70 from the home position, in response to magnetic forces generated by theelectromagnetic coil structure29″, and exerted against the permanent magnet embedded there within, whereupon the integrated rotation limiting occurs, and the scan mirror and magnet rotor subassembly is stopped at 20 degrees rotation about the scan axis, from the home position.

FIGS. 29C and 29D illustrate the silicone torsionally-distortedframe26″ shown inFIGS. 29A and 29B, wherein silicone hinges have undergone 20 degrees of twist during maximum rotation about the scan axis, when stopped by the omnidirectionalmotion limiting structure73.

In summary, the design specifications for the second illustrative embodiment are as follows:

(1) thescan mirror27″ is normally located at the 35 degree home position—before being driven by theelectromagnet coil29″;

(2) during scanning operations, thescan mirror27″ sweeps a total of 24 degrees about this home position, which implies 12 degrees in the clockwise direction and 12 degrees in the counterclockwise direction;

(3) the integrated rotation-motion limiter73 and corresponding stop surfaces on theframe holder26″ stop rotation of the rotor in the clockwise direction when the scan mirror rotates 8 degrees beyond its normal 12 degree swing in the clockwise direction (i.e. 12+8=20 degrees); and

(4) theintegrated rotation limiter73 and corresponding stop surfaces on theframe holder26″ stop rotation of the rotor in the counter-clockwise direction when the scan mirror rotates 8 degrees beyond it normal 12 degree swing in the counter-clockwise direction (i.e. 12 +8=20 degrees).

During this maximum angular swing of 20 degrees, when therotor subassembly25″ stop(s) hits or strikes corresponding stop surface on thestator structure26″. The silicone torsional hinges68E,68F will have undergone 20 degrees of twist-type distortion, and automatically generate a linear rotor restoring force which acts to return the scan mirror andmagnet rotor subassembly25″ back to the “home” position.

Specification of the Omni-Directional Motion Limiting Structures Integrated within the Laser Scanning Assembly of Second Illustrative Embodiment

FIG. 29E illustrates the laser scanning assembly ofFIG. 25A, with its scan mirror and magnet rotor subassembly rotated to an extreme clockwise position, and showing theintegrated motion limiter73B striking thethermoplastic frame holder25″, and limiting the rotation of the scan mirror and magnet rotor subassembly, to the position shown inFIG. 29B.

FIG. 29F illustrates the laser scanning assembly ofFIG. 25A, configured with its scan mirror andmagnet rotor subassembly25″ rotated to an extreme counter-clockwise position, and showing theintegrated motion limiter73A striking thethermoplastic frame holder26″, and limiting the rotation of the scan mirror and magnet rotor subassembly, to the position shown inFIG. 29B.

When configured in these two extreme rotational positions, the silicone torsional hinges26E″ and26F″ elastically distorted, as shown inFIGS. 29C and 29D, and generate restoring or returning forces that are linear with respect to angle of rotation.

FIGS. 30A through 30C illustrate the laser scanning assembly ofFIG. 25A, subjected to external shock forces exceeding a particular threshold, and showing the displacement of the scan mirror and magnet rotor subassembly along the x axis direction, and limited by theintegrated motion limiters73B contacting the stop projections/projections26H1″26H3″ on thethermoplastic frame holder26″, as best shown inFIG. 30C.FIGS. 30D and 30E is a perspective view of the silicone torsionally-supportedframe68 in the configured laser scanning assembly ofFIGS. 30A through 30C, showing the limited displacement of the silicone torsional hinges68C,68D along the x axis direction.

FIGS. 31A through 31C illustrate the laser scanning assembly ofFIG. 25A, subjected to external shock forces exceeding a particular threshold, and showing the displacement of the scan mirror and magnet rotor subassembly along the y axis direction, and limited by the integrated motion limiters (i.e. silicone frame)68E contacting theupper portion26F″ of thethermoplastic frame holder68, as shown.FIG. 31D illustrates the silicone torsionally-supported frame in the configured laser scanning assembly ofFIGS. 31A through 31C, showing the limited displacement of the silicone torsional hinges68C,68D along the y axis direction.

FIGS. 32A through 32C illustrate the laser scanning assembly ofFIG. 25A, subjected to external shock forces exceeding a particular threshold, and showing the displacement of the scan mirror and magnet rotor subassembly along the z axis direction, and limited by theintegrated motion limiter73C,76D contacting thethermoplastic frame holder26 at frame surfaces26H5″ and26H6″, as shown inFIG. 32C.FIGS. 32D and 32E illustrate the silicone torsionally-supportedframe26″ in the configured laser scanning assembly ofFIGS. 32A through 32C, showing the limited displacement of the silicone torsional hinges26C″ and26D″ along the z axis direction.

All components of the laser scanning assembly, except for themagnet28″,elastomeric frame element26″, andelectromagnetic coil windings71A,71B can be a molded as thermoplastic parts using suitable thermoplastic material (e.g. polycarbonate, acrylonitrile butadiene styrene, and/or synthetic polymers known generically as polyamides, etc). Thepermanent magnet28″ can be realized using Neodymium Iron Boron Type N50 magnetic material, or similar material. The elastomeric hinge element55 can be injection molded from a LSR (Liquid Silicone Rubber) material, such as Momentive Performance #2030 Silicone or Shin-Etsu KE2090-30AB Select Hesive with enhanced adhesive properties. The layer of adhesive can be aDow Corning 734 adhesive, or similar material, and the primer layer could be a GE SS4004P or similar material.

In the second illustrative embodiment described above, thetorsional posts26C″ and26D″ are shown snap-fit onto theapertures26D″ and26E″, respectively, formed in thethermoplastic frame holder26. It is understood, however, that these torsional, silicone hingedelements26C″ and26D″ can be over-molded about the top and bottom portion of the thermoplastic frame holder. With this technique, it is possible to increase the stability of the scan element and improve the ease of assembly. Also, it is expected that the performance of an over-molded, torsional,silicone scan rotor25″ should degrade more gracefully over time, as it is less susceptible to outside contaminants and environmental conditions. The over-molded, torsional, silicone hinges (i.e. posts)26E″ and26F″ will return the siliconeframe rotor subassembly25″ to a “home position” when at rest. This “return to home” feature is essential to maintaining a stable scan line during scanner operation. By over-molding the silicone torsional posts about the thermoplastic frame holder, it is expected that part-to-part variation will be minimized by eliminating operator variation, and this will result in a more consistent scan line. The inherent properties of silicone will allow for a smoothly operating scanning mechanism that will see minimal performance degradation over time.

MODIFICATIONS THAT COME TO MIND

Having described the illustrative embodiments, several variations and modifications readily come to mind.

In the illustrative embodiments, the laser scanning modules has been shown to have the form factor of parallel-piped shaped engines, where opposite sides are generally parallel to each other. It is understood, however, that in alternative embodiments, the laser scanning module of the present disclosure can have non-parallel-piped form factors (e.g. cylindrical-shaped, drum shaped, oval-shaped, arbitrary-shaped 3D modules). Also, the laser scanning assemblies of the present disclosure can be installed in all kinds of code symbol reading systems without the use of module or engine housings, and can be realized directly on optical benches, PC boards, and numerous other environments.

It is understood that the laser scanning assembly of the illustrative embodiments may be modified in a variety of ways which will become readily apparent to those skilled in the art in view of the novel teachings disclosed herein. All such modifications and variations of the illustrative embodiments thereof shall be deemed to be within the scope of the Claims appended hereto.

Claims (20)

The invention claimed is:

1. A laser scanning assembly, comprising:

a frame holder mounted stationary relative to a housing;

a silicone frame supporting a scan mirror and a magnet, the silicone frame comprising a pair of silicone torsional hinges over-molded to the frame holder, wherein the pair of silicone torsional hinges: (i) is aligned along a scan axis passing through the silicone frame; (ii) torsionally supports the scan mirror; and (iii) allows the scan mirror and the magnet to oscillate freely about the scan axis passing through the pair of silicone torsional hinges; and

an omni-directional rotor motion limiting structure for limiting rotational and translational motion of the frame holder and silicone frame.

2. The laser scanning assembly ofclaim 1, wherein the pair of silicone torsional hinges generates an elastic returning force to the scan mirror and the magnet, the magnitude of which is linearly proportional to the magnitude of the angle of rotation of the scan mirror and the magnet about the scan axis.

3. The laser scanning assembly ofclaim 1, wherein:

the silicone frame has a top end and a bottom end; and

the omni-directional rotor motion limiting structure comprises a pair of stops formed on the top and bottom ends of the silicone frame.

4. The laser scanning assembly ofclaim 3, wherein:

the omni-directional rotor motion limiting structure comprises projections extending from the frame holder; and

the projections strike the pair of stops when the laser scanning assembly is subject to external shock forces, thereby limiting the angular rotational displacement of the scan mirror and the magnet.

5. The laser scanning assembly ofclaim 4, wherein:

the silicone frame has a top surface and a bottom surface; and

the frame holder strikes the top and bottom surfaces of the silicone frame when the laser scanning assembly is subjected to the external shock forces, thereby limiting the linear displacement of the scan mirror and the magnet along a first coordinate direction parallel with the scan axis.

6. The laser scanning assembly ofclaim 5, wherein:

the silicone frame has a front surface and a rear surface;

the frame holder has a front surface; and

the rear surface of the silicone frame strikes the front surface of the frame holder when the laser scanning assembly is subject to external shock forces exceeding a particular threshold, thereby limiting the linear displacement of the scan mirror and the magnet along a second coordinate axis, orthogonal to the front surface of the frame holder, in response to the external shock forces.

7. The laser scanning assembly ofclaim 6, wherein the pair of stops on the top and bottom ends of the silicone frame strike the projections extending from the frame holder when the laser scanning assembly is subjected to external shock forces exceeding the particular threshold, thereby limiting the linear displacement of the scan mirror and the magnet along a third coordinate axis, orthogonal to the scan axis and parallel to the front surface of the frame holder, in response to the external shock forces.

8. The laser scanning assembly ofclaim 3, wherein the omni-directional rotor motion limiting structure comprises:

a set of stop projections and/or stop surfaces on the rear surface of the frame holder; and

a plate structure mounted over the magnet and having a first pair of projections formed along a first axis for engaging with one or more of the stop projections and/or stop surfaces on the frame holder, thereby limiting the rotational displacement of the scan mirror and the magnet about the scan axis, when the laser scanning assembly is subjected to external shock forces exceeding the predetermined threshold.

9. The laser scanning assembly ofclaim 8, wherein:

the plate structure comprises a second pair of projections formed along a second axis, orthogonal to the first axis; and

the second pair of projections strike one or more of the stop projections and/or stop surfaces on the frame holder, thereby limiting the linear displacement of the scan mirror and the magnet along a first coordinate direction orthogonal with the scan axis, in response to the external shock forces.

10. The laser scanning assembly ofclaim 9, wherein:

the frame holder has an opening with a top opening surface and a bottom opening surface; and

the top surface of the silicone frame strikes the top opening surface of the opening on the frame holder and/or the bottom surface of the silicone frame strikes the bottom opening surface of the opening on the frame holder, when the laser scanning assembly is subject to external shock forces exceeding the particular threshold, thereby limiting the linear displacement of the scan mirror and the magnet along a second coordinate axis, parallel to the scan axis.

11. The laser scanning assembly ofclaim 10, wherein the second pair of projections of the plate structure strikes one or more of the stop projections and/or stop surfaces on the frame holder, when the laser scanning assembly is subjected to external shock forces exceeding the particular threshold, thereby limiting the linear displacement of the scan mirror and the magnet along a third coordinate axis, orthogonal to the scan axis and the first and second coordinate axes.

12. The laser scanning assembly ofclaim 1, wherein the silicone frame is molded from a liquid silicone rubber.

13. The laser scanning assembly ofclaim 1, wherein each of the pair of torsional hinges comprises a torsional post.

14. The laser scanning assembly ofclaim 13, wherein each of the torsional posts has a circular cross-sectional dimension.

15. The laser scanning assembly ofclaim 13, wherein each of the torsional posts has a rectangular cross-sectional dimension.

16. The laser scanning assembly ofclaim 1, wherein the frame holder comprises a support portion mounted within a recess formed in the housing.

17. The laser scanning assembly ofclaim 1, wherein a first side and a second side of the silicone frame reside on the same side of the scan axis.

18. A laser scanning module comprising:

a laser drive circuit for generating laser drive current signals to a laser source; and

a laser scanning assembly, comprising:

a frame holder mounted stationary relative to a housing;

a silicone frame supporting a scan mirror and a magnet, the silicone frame comprising a pair of silicone torsional hinges over-molded to the frame holder, wherein the pair of silicone torsional hinges: (i) is aligned along a scan axis passing through the silicone frame; (ii) torsionally supports the scan mirror; and (iii) allows the scan mirror and the magnet to oscillate freely about the scan axis passing through the pair of silicone torsional hinges; and

an omni-directional rotor motion limiting structure for limiting rotational and translational motion of the frame holder and silicone frame.

19. The laser scanning module ofclaim 18, wherein:

the silicone frame has a top end and a bottom end; and

the omni-directional rotor motion limiting structure comprises a pair of stops formed on the top and bottom ends of the silicone frame.

20. A code symbol reading system comprising:

a system housing;

a laser source mounted in the system housing;

a laser drive circuit, mounted in the system housing, for generating laser drive current signals to the laser source; and

a laser scanning assembly, comprising:

a frame holder mounted stationary relative to the system housing;

a silicone frame supporting a scan mirror and a magnet, the silicone frame comprising a pair of silicone torsional hinges over-molded to the frame holder, wherein the pair of silicone torsional hinges: (i) is aligned along a scan axis passing through the silicone frame; (ii) torsionally supports the scan mirror; and (iii) allows the scan mirror and the magnet to oscillate freely about the scan axis passing through the pair of silicone torsional hinges; and

an omni-directional rotor motion limiting structure for limiting rotational and translational motion of the frame holder and silicone frame.

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